Question

objective 2: continental drift

1. who was alfred wegener? what was his belief about the positions of present-day continents?
2. discuss the 4 pieces of evidence for alfred wegener’s hypothesis.
3. why did most scientists reject wegener’s hypothesis?

Explanation:

Sub - question 1

Alfred Wegener was a German meteorologist and geophysicist. His belief was that the present - day continents were once part of a single supercontinent called Pangaea and have since drifted apart to their current positions.

1. Fossil Evidence: Similar fossils of plants (e.g., Glossopteris) and animals (e.g., Mesosaurus) are found on continents that are now far apart. This suggests the continents were once connected as these organisms could not have crossed the vast oceans.
2. Rock and Mountain Evidence: Mountain ranges with similar rock types and structures are found on different continents. For example, the Appalachian Mountains in North America and the Caledonian Mountains in Europe match in terms of rock composition and structure, indicating they were once part of the same mountain range before the continents drifted.
3. Climate Evidence: Glacial deposits and evidence of tropical climates in regions that are now temperate or polar. For instance, glacial till (deposits left by glaciers) is found in South America, Africa, India, and Australia, suggesting these areas were once part of a single landmass near the South Pole. Also, coal deposits (formed in tropical swamps) are found in polar regions, indicating those regions were once near the equator.
4. Continental Fit: The continents, especially South America and Africa, appear to fit together like pieces of a jigsaw puzzle. The shape of the coastlines of these continents suggests they were once joined.

Most scientists rejected Wegener's hypothesis because he could not provide a satisfactory mechanism for how the continents moved. He proposed a mechanism related to the "pole - fleeing force" and "tidal force" which were not supported by physical laws. Also, the scientific community at the time was more accustomed to the idea of a static Earth, and the concept of continental drift was a radical departure from the established geological thinking.

Answer:

Alfred Wegener was a German meteorologist and geophysicist. He believed that present - day continents were once part of a single supercontinent (Pangaea) and have drifted to their current positions.

Sub - question 2